The spread of bacteria and infections, initially associated with an increased number of hospital-acquired infections, has now extended into the community causing severe and difficult to treat diseases. Additionally, many of those diseases are evoked by bacteria that have become resistant to antibiotics. Overcoming the ability of bacteria to develop resistance will potentially reduce the burden of these infections on the healthcare systems worldwide and prevent thousands of deaths each year.
The nano-scale particles are promising candidates to fight bacteria, since developing of resistance to their action is less likely to occur. Nanoparticles (NPs) can be incorporated into polymeric matrices to design a wide variety of nanocomposites. Such nano-structures consisting of inorganic and inorganic/organic NPs represent a novel class of materials with a broad range of applications.
This thesis is about the development of antibacterial nano-structured materials aimed at preventing the spread of bacteria. To achieve this, two versatile physicochemical and biotechnological tools, namely sonochemistry and biocatalysis were innovatively combined. Ultrasound irradiation used for the generation of various nano-structures and its combination with biocatalysts (enzymes) opens new perspectives in materials processing, here illustrated by the production of NPs coated medical textiles, water treatment membranes and chronic wound dressings.
The first part of the thesis aims at the development of antibacterial medical textiles to prevent the bacteria transmission and proliferation using two single step approaches for antibacterial NPs coating of textiles. In the first approach antibacterial zinc oxide NPs (ZnO NPs) and chitosan (CS) were deposited simultaneously on cotton fabric by ultrasound irradiation. The obtained hybrid NPs coatings demonstrated durable antibacterial properties after multiple washing cycles. Moreover, the presence of biopolymer in the NP hybrids improved the biocompatibility of the material in comparison with ZnO NPs coating alone.
In the second approach, a simultaneous sonochemical/enzymatic process for durable antibacterial coating of cotton with ZnO NPs was carried out. The enzymatic treatment provides better adhesion of the ZnO NPs and, as a consequence, enhanced coating stability during exploitation. Likewise to the antibacterial coatings obtained in the first approach, the antibacterial efficiency of these textiles was maintained after multiple intensive laundry regimes used in hospitals. The NPs-coated cotton fabrics inhibited the growth of the most medically relevant bacteria species.
In the second part of the thesis, hybrid antibacterial biopolymer/silver NPs and cork matrices, were enzymatically assembled into an antimicrobial material with potential for water remediation. Intrinsically antibacterial amino-functional biopolymers, namely CS and aminocellulose were used as doping agents to stabilize colloidal dispersions of silver NPs (AgNPs), additionally providing the particles with functionalities for covalent immobilization on cork to impart durable antibacterial effect. The biopolymers promoted the antibacterial efficacy of the obtained nanocomposites in conditions simulating a real situation in constructed wetlands.
In the last, third part of the thesis, a bioactive nanocomposite hydrogel for wound treatment was developed. Sonochemically synthesized epigallocatechin gallate nanospheres (EGCG NSs) were incorporated and simultaneously crosslinked enzymatically into a thiolated chitosan hydrogel. The potential of the generated material for chronic wound treatment was evaluated by assessing its antibacterial properties and inhibitory effect on myeloperoxidase and collagenase biomarkers of chronic wound infection. Sustained release of the EGCG NSs from the biopolymer matrix was achieved. The latter, coupled with the good biocompatibility of the hydrogel, suggested its potential for chronic wound management.

The antimicrobial finishing is a must for production of medical textiles, aiming at reducing the bioburden in clinical wards and consequently decreasing the risk of hospital-acquired infections. This work reports for the first time on a simultaneous sonochemical/enzymatic process for durable antibacterial coating of cotton with zinc oxide nanoparticles (ZnO NPs). The novel technology goes beyond the "stepwise" concept we proposed recently for enzymatic pre-activation of the fabrics and subsequent sonochemical nano-coating, and is designed to produce "ready-to-use" antibacterial medical textiles in a single step. A multilayer coating of uniformly dispersed NPs was obtained in the process. The enzymatic treatment provides better adhesion of the ZnO NPs and, as a consequence, enhanced coating stability during exploitation. The NPs-coated cotton fabrics inhibited the growth of the medically relevant Staphylococcus aureus and Escherichia coli respectively by 67% and 100%. The antibacterial efficiency of these textile materials resisted the intensive laundry regimes used in hospitals, though only 33% of the initially deposited NPs remained firmly fixed onto the fabrics after multiple washings. (C) 2015 Elsevier B.V. All rights reserved.

The antimicrobial finishing is a must for production of medical textiles, aiming at reducing the bioburden in clinical wards and consequently decreasing the risk of hospital-acquired infections. This work reports for the first time on a simultaneous sonochemical/enzymatic process for durable antibacterial coating of cotton with zinc oxide nanoparticles (ZnO NPs). The novel technology goes beyond the

Laccase-assisted assembling of hybrid biopolymer-silver nanoparticles and cork matrices into an antimicrobial material with potential for water remediation is herein described. Amino-functional biopolymers were first used as doping agents to stabilize concentrated colloidal dispersions of silver nanoparticles (AgNP), additionally providing the particles with functionalities for covalent immobilization onto cork to impart a durable antibacterial effect. The solvent-free AgNP synthesis by chemical reduction was carried out in the presence of chitosan (CS) or 6-deoxy-6-(omega-aminoethyl) aminocellulose (AC), leading to simultaneous AgNP biofunctionalization. This approach resulted in concentrated hybrid NP dispersion stable to aggregation and with hydrodynamic radius of particles of about 250 nm. Moreover, laccase enabled coupling between the phenolic groups in cork and amino moieties in the biopolymer-doped AgNP for permanent modification of the material. The antibacterial efficiency of the functionalized cork matrices, aimed as adsorbents for wastewater treatment, was evaluated against Escherichia coli and Staphylococcus aureus during 5 days in conditions mimicking those in constructed wetlands. Both intrinsically antimicrobial CS and AC contributed to the bactericidal effect of the enzymatically grafted on cork AgNP. In contrast, unmodified AgNP were easily washed off from the material, confirming that the biopolymers potentiated a durable antibacterial functionalization of the cork matrices.

Advances in development of nanocomposite gels that provide localized delivery of pharmaceuticals for treatment of chronic wounds are being highly pursued. To design such materials, the use of natural polymers is recommendable due to their intrinsic biocompatibility and biodegradability. Moreover, the use of biocatalytic approaches for composite assembling is preferred compared to harsh chemical cross-linking reagents. In this study, HRP catalyzed cross-linking of hydrogels from aqueous solution of thiolated chitosan to in situ incorporated sonochemically synthesized epigallocatechin gallate nanospheres (EGCG NSs). The potential of the generated NSs for chronic wound treatment was evaluated by assessing their antibacterial properties and inhibitory effect on myeloperoxidase and collagenasemajor enzymes of inflamed chronic wounds. The EGCG NSs displayed better antibacterial and antienzymatic properties compared to the EGCG in solution. Also, the NSs were incorporated into hydrogels without affecting their integrity and were released intact in a sustained manner (during 6 days). The cytotoxicity assay confirmed the compatibility of the hybrid material with human fibroblasts that suffered less than 10% decrease in viability during 24 h. Release of functional phenolic NSs and good compatibility of the composite hydrogel with cells suggested its potential application in chronic wound management.

This work is about the synthesis of hybrid nanocomposite hydrogels comprising a thiolated chitosan platform that incorporates epigallocatechin gallate nanospheres as active polyphenolic agents for wound healing applications. The phenolic nanospheres were prepared using an industry-attractive, low-cost and fast sonochemical technology, whereas the gel formation was achieved via a green approach involving the enzymatic cross-linking with horseradish peroxidase, avoiding the use of harsh chemical cross-linkers. The superior functional properties of the phenolic nanospheres compared to their molecular counterparts are demonstrated by better attenuation of the chronicity factors found in non-healing wounds. Release of the intact and functional phenolic nanospheres coupled to good biocompatibility of the system during several days, reveals potential of this hybrid material as a dressing with prolonged activity for chronic wound management.

Textiles are good substrates for growth of microorganisms especially under moisture and temperature conditions found in hospitals. Microbial shedding from the body occurs continuously at contact of the patient with textile materials used in medical practice, contributing to the occurrence of hospital acquired infections. Thus, the use of efficient antimicrobial textiles is necessary to prevent the transfer of pathogens and the infection incidence. In this work, hybrid antimicrobial coatings were generated on cotton fabrics by means of a one-step simultaneous sonochemical deposition of ZnO nanoparticles (NPs) and chitosan. The process was further optimized in terms of reagents concentration and processing time in order to improve the antibacterial properties of the fabric and ensure their biocompatibility. The highest antibacterial activity of the fabrics against two medically relevant bacterial species was achieved in a 30 min sonochemical coating process using 2 mM ZnO NPs suspension. When chitosan was simultaneously deposited with the same amount of ZnO, the obtained hybrid NPs coating displayed higher by 48 and 17 % antibacterial activity against Staphylococcus aureus and Escherichia coli, respectively. The presence of biopolymer also improved the durability of the antimicrobial effect of the coatings by 21 % for Staphylococcus aureus and 40 % for Escherichia coli, evaluated after applying multiple washing cycles at hospital laundering regimes. Finally, 87 % biocompatibility improvement supported by fibroblast viability was observed for the hybrid ZnO/chitosan coating compared to the steady decrease of cells viability over one week in contact with the fabrics coated with ZnO alone.

Textiles are good substrates for growth of microorg
anisms especially under moisture and
temperature conditions found in hospitals. Microbia
l shedding from the body occurs
continuously at contact of the patient with textile
materials used in medical practice, contributing
to the occurrence of hospital acquired infections.
Thus, the use of efficient antimicrobial textiles
is necessary to prevent the transfer of pathogens a
nd the infection incidence. In this work, hybrid
antimicrobial coatings were generated on cotton fab
rics by means of a one-step simultaneous
sonochemical deposition of ZnO nanoparticles (NPs)
and chitosan. The process was further
optimized in terms of reagents concentration and pr
ocessing time in order to improve the
antibacterial properties of the fabric and ensure t
heir biocompatibility. The highest antibacterial
activity of the fabrics against two medically relev
ant bacterial species
was achieved in a 30 min
sonochemical coating process using 2 mM ZnO NPs sus
pension. When chitosan was
simultaneously deposited with the same amount of Zn
O, the obtained hybrid NPs coating
displayed higher by 48 and 17 % antibacterial activ
ity against
Staphylococcus aureus
and
Escherichia coli
, respectively. The presence of biopolymer also imp
roved the durability of the
antimicrobial effect of the coatings by 21 % for
Staphylococcus aureus
and 40 % for
Escherichia
coli
, evaluated after applying multiple washing cycles
at hospital laundering regimes. Finally, 87
% biocompatibility improvement supported by fibrobl
ast viability was observed for the hybrid
ZnO/chitosan coating compared to the steady decreas
e of cells viability over one week in contact
with the fabrics coated with ZnO alone.

The objective is a first industrial application of the eco-innovative solution ERUTAN (nature backwards), with the intention to reach global replication of the environmentally friendly production process for wool floor coverings. ERUTAN is developed at pilot scale by three SME/s in cooperation with European R&D partners and brings a high added value to the global carpet market. The main objectives and steps beyond the state-of-the-art of this project are: i) up-scaling of an innovative, sustainable enzymatic wool scouring method, ii) up-scaling of a novel enzymatic process for bonding between the yarns and supporting material of the carpet. WP2, realisation of an industrial enzymatic wool scouring process, enables sheep farmers worldwide to scour their own raw wool environmentally responsible. The carpet backing approach brings considerable energy saving and low, if any, carbon footprint using naturally based adhesives and enzymes.
ERUTAN is the first real innovation in manufacturing of textile floor covering since 1960. Although the single production steps remain equal, the environmental impact and production method change greatly. The pilot line for wool scouring, located at partner JMS, will be adapted to reach the industrial standard of scouring 10 tons of raw wool within 6 hours. Intensification is further achieved by optimizing enzyme formulation and conditions for application. Regarding the enzymatic bonding process 4 tasks are planned for WP3: Identification of potential providers for adhesives precursors and enzymes, Up-scaling backing line, Up-scaling adhesive paste, Optimization of process parameters and paste application technology. Within LCA work package, input of ERUTAN carpet after its use phase into a second life such as substrates for the agro and food industry, is taken into account. In WP5, business plan related to the exploitation and commercialization of the industrially developed processes and products. Dissemination activities are in WP6.